Lightning arrester



Patented May 1, 1928.

8,310 I U NI T.E D1ILS T E S P AT N 0 F GEORGE'B'; FOLDS1OFEVANSTON ILLINOIS,,&SSIGNOR TO COOK ELECTRIC COMPANY, OF CHICAG-0,.ILLINOIS, A GOEPQRATION OF ILLINOIS.

LIGHTNING ARRESTER.

Application filed May 28,

This invention relates to lightning arrosters or gap dischargers and more particularly to improved lightning arresters or dischargcgap units designed tornse in connection vwith comparatively low voltage electrio circuits, such as. telephone, telegraph and signal ,,systems to provide for high potential discharges 1 One object. of this inventionds to provide a gap discharger .of .the character indicated wherein the. spacing otthe; conducting mom-- hers-comprising, the discharge-gap is .very accuratelysand uniformly maintained.

A furtherrobject ofithis invention isto providecins aideviceofv the character indicated. -.n11itary. construction whichv is susceptible to rapid commercial production and assembly in largeiquantities and which is at the sametimeprovided with very accurately spaced.discharge-electrodes, such accurately spaced members.insuring.v the uniform and dependable electricalfoperation of. the de- V108. v

A further particularaim of this inven tion is to provide conducting members form ing the dischargergap that are constructed in a. manner .to readilypp'ermit the removal or escapebf. the products of deterioration,

resultinggfromiarcing betweenthe conducts. mg members..p-.... o

Other objects of. the invention :will become apparent: from the following description and accompanying drawings and the appended" claims. s

i For .purposes :of. description and illustra tion, sasspecific embodiment of this inventionwis shown in the accompanying drawings,; in? .whichfimi Figurealwis aside view of a device embodyingthe invention;w V I Fig. 2...is.a view .takenat right angles to tliat-.,of Fig. 1,1 showing the device embodying the. invention asretained between a pair of spring. supporting and connecting clips;

Fig. (Sis an end view of a device as shown in Fig.3;

Figd i is a view similar to, that of Fig. 1, but showing a slightly..modified form of structure.

1 The device forming the subject matter of this invention .Inaycomprisea unitary structure: or assembly: 10f1n the formv of a discharge ,gap .whichiqprovides apath for high potentialmdischarges. between the terminals of any device :whichit-is desired to protect 1923. Serial No. 642,023..

against the efiects of such high potentials.

In the modification shown in the illustrations, the assembl 10 may be supported ew tamed and electrically. connected to the desired electrical. terminals by means of a pair of spring clips 11 and 12,between which the unit 10 forms a high potential discharge path.

The unit 10 briefi may comprise a block,

to form a dove-tail joint between a ten0n portion 15 formed uponthe block 13 and a mortise portion comprising a pair of flanges 16 and 17 formednponthe electrode plate 14-. .The plate 11 may beconveniently electrically. and. mechanicallyspaced from the carbon block 18 by means of a layerof dielectric 18'comp0sed of any suitable insulating material preferably. pliableand such as celluloid, The dielectric18 maybepref- I erablycomposed of material which will meltv or be destroyedunder severe heat and thus permit the arrester, to ground under continued arc. I v

After the electrode plate 14; and the dielectric 18 are properly assembled upon the i carbon block, the corners of the flanges 16 thus effectively and permanently retaining these'parts in their proper relative positions.

A groove 19 at one edge of the carbon bloclr13 provides means for slidablyreceiving the spring contact andsupport ,12. The electrode platel may also be provided with a number of struck-up portionsor detents 20, spaced in a manner to serve a purpose similar to that of the groove 19 by slidably receiving the spring contactorsupport 11. It will be understood that the springcontacts 11 and 12 as here shown partly in section may be extended in any desired manner for connection with switchboards or other electrical apparatus.

and 17 may be bent over as indicated at 14c,

The layer of dielectric 18 may be provided with a plurality of perforations as atQl arranged preferably along the center line ofv the tenon portion 15. A. portion of the electrode plate 14: adjacent these perforations cooperates with the adjacent portions of the carbon block, thus'forming the electrodes of the gap discharge-r. The path ofthe high potential discharge through the device in cludes the arcing space between these electrode members at the perforations.

In order to insure an arcuate and uniform spacing of the discharge portions of the electrodes, the electrode plate 1 f may be formed with an embossed or struck-down ridge 22 extending across the various perforations 2']. and firmly resting upon the dielectric mate rial adjacent the perforations. The use of such a ridge insures an accurate spacing of the electrodes at points in proximity of the perforations by a distance equal to the thickness of the dielectric. In other words, in case of any irregularities or unevenness in the format-ion of the electrode plate, the area of contact between the plate and the dielectric will always include the ridge 22. Consequently, the ridge which forms a discharge portion will be positioned at a predetermined distance from the carbon block depending upon the thickness of the dielectric used.

After excessive or continued arcing, the discharge portions of the electrodes may become deteriorated to a certain degree. In order to prevent possible short circuiting of the arrester or an inaccurate spacing effect of the electrodes, it is desirable that the products of deterioration should be permitted to escape or should be removable. Accordingly, the electrode plate 14 may be provided adjacent to each of the discharge portions with perforations 23 at either side of the depressed ridge 22.

The modification of the device as shown in Fig. 4.- is similar to that shown in Fig. 1, except that the perforations 23 in the electrode plate '14 are omitted. The use of such a structure may be preferable in certain instances, such for example, as where it is necessary to exclude all particles of dirt, dust or other foreign matter from the dis charge portions. In this modification, pockets are provided between the members 13 andla at each side of the ridge 22 sufliciently large to allow the products of deterioration to accumulate for some time. They may be removed when necessary by sliding the electrode plate off the tenon portion of the car bon block.

It will be noted that by using structures of above described types, a large number of electrode members may be manufactured and assembled without the necessity of carefully fitting the various parts. since the length of the discharge gap will always be accurately determined by the thickness of the dielectric. *urthermore, the same type of parts may be used in producing gap dischargers having a variety of electrode spacings, each suitable for a particular purpose. To produce a lightning arrester having different elect-rode spacing, it is merely necessary to select a dielectric layer of the proper thickness.

In the claims I use the words conducting member in the form of a block as indicative of any kind or character of mate to which the sheet metal electrode may be afiixed.

It is not intended that this invention be limited to the specific embodiment herein illustrated and described, but it is capable of many variations and modifications which may come within the scope and spirit of the invention, as set forth in the following claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent in the United States, is:

1. A discharge gap comprising a conducting member in the form of a block, a second conducting member formed of sheet metal and clamped to a portion of said block, and a perforated layer of dielectric material separating said block and said second conducting member from electrical contact with each other, one of said conducting members having longitudinally extending means for cooperating at a. perforation in the dielectric material to form av discharge portion which provides a discharge gap of a predetermined length determined by the thickness of the dielectric material.

2. A discharge gap comprising a conducting member in the form of a block, a second conducting member formed of sheet metal and clamped to a portion of said block, and a perforated layer of dielectric material separating said block and said secondconducting member from electrical contact with each other, said conducting members cooperating at a perforation in the dielectric material to form a discharge gap of a predetermined length, said sheet metal conducting member being formed with a struckdown ridge extending across said perforation and forming a discharge portion resting firmly upon the dielectric material adjacent said perforation.

8. A discharge gap comprising a conducting member in the form of a block, a second conducting member formed of sheet metal and clamped to a portion of said block, and a perforated layer of dielectric material separating said block and. said second conducting member from electrical contact with each other, said conducting members cooperating at a perforation in the dielectric material to form a discharge gap of a predetermined length, said second conducting member being formed with perforations adjacent the discharge gap for permitting the escape therethrough of the products of deterioration at the gap.

4. A lightning arrester comprising a block of conducting material, an electrode plate crimped upon a portion of said block, and a layer of dielectric material separating said plate and said block from electrical contact with each other, said dielectric being provided with a perforation beneath said plate,

tion and forming a discharge portion resting firmly upon the dielectric material adjacent said Perforation.

5. A lightning arrestercomprising a block of conducting material, an electrode plate fixed upon a portion ofsaid block, and a layer of dielectric material separating said plate and said block from electrical contact with each other, said dielectric being provided with a perforation beneath said plate,

and said plate being formed with an embossed ridge extending across said perforation and forming a discharge port-ion resting firmly upon the dielectric material adjacent said perforation, and perforations in said plate at either side of said ridge.

6. A discharge gap comprising a block of conducting material, an electrode plate crimped upon a portion of said block, a thin layer of flexible sheet dielectric material separating said plate and said block from electrical contact with each other, said dielectric being perforated to provide for a discharge gap beneath said plate, and means on said electrode plate resting firmlyupon said dielectric material and forming a discharge portion across said perforation therein said sheet of dielectric material also beingof a uniform and accurately predetermined thickness equal to the effective length of the discharge gap.

In witness whereof, I have hereunto subscribed my name. GEORGE R. FOLDS. 

